1. Field of the Invention
The present invention relates to storage units and storage methods for storing articles such as reticles and wafers.
2. Description of the Related Art
Patent Literature 1 (JP 4215079B) discloses, regarding a unit for storing articles such as reticles:
providing a reticle carousel and a pod carousel, and superposing the reticle carousel over the pod carousel;
providing two hands configured to move up and down, a pod opener, a buffer for temporary placement of a pod, and a loading port for bringing in or out the pods, and transferring the pods and reticles; and blowing clean air into the carousels in a down-flow manner.
Patent Literature 2 (JP 2008-219032A) discloses handling reticles by accommodating each reticle in a double case constituted by an inner case and an outer case (pod).
To store more delicate wafers or reticles that record a more delicate pattern, a cleaner atmosphere needs to be provided, and simply blowing clean air into carousels in a down-flow manner is insufficient. In particular, when storing reticles to be exposed with EUV (Extreme Ultra Violet) light, reticles having an extremely fine pattern, or the like, the atmosphere for storage not only needs to simply have a low dust concentration, but also needs to be chemically clean and have an extremely low moisture content.